Until now such dispenser and sealing cap assemblies were made as one single part by moulding of a rigid plastic material such as polypropylene. In fact, the spring hinges provided on such assemblies between the spout part and the sealing cap only correctly fulfill their function, which is to ensure two stable positions of the cap in relation to the dispensing part, when they are made of a rigid plastic material.
Such spring hinges are known, for example, from the French Patent Nos. 1 402 900 and 78 03 713.
On the known spout and sealing cap assemblies made as one single part with the spring hinge from a rigid plastic material, the tightness between the spout part and the neck of the container must be ensured by means moulded onto the dispensing part, in particular by lips and/or skirts cooperating with the neck of the container. Because of the rigidity of the material of which they are made, these sealing means are unable to compensate possible defects of the neck, which adversely affects the tightness. The use of separate flexible seals on the spout part which would permit a compensating of such defects is not always possible and would increase the cost price of the spout and cap assembly.
Another problem is experienced with the dispenser and sealing cap assemblies provided for flexible tubes containing pasty materials, e.g. toothpaste tubes. Nowadays, these tubes are made more and more from a flexible plastic material, in particular polyethylene or from a complex or multilayer structure having an outside polyethylene film. Under these conditions, a spout and sealing cap assembly, made as one single part from a rigid plastic material such as polypropylene so as to enable the spring hinge provided between the two parts to fulfill its function, cannot be welded directly onto the flexible tube. Rather, this type of assembly must be screwed onto a threaded neck end of a flexible plastic material, in particular polyethylene, welded onto the actual body of the flexible tube. It would be desirable to be able to make spout and sealing cap assemblies with spring hinge which can be fixed directly by welding onto the body of flexible tubes.